检索结果-南通市图书馆

A TRUST-REGION METHOD FOR SOLVING TRUNCATED COMPLEX SINGULAR VALUE DECOMPOSITION

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2024年第4期42卷 999-1031页

作者： Jiaofen Li Lingchang Kong xuefeng duan Xuelin Zhou Qilun Luo School of Mathematics and Computing Science Guangxi Colleges and Universities Key Laboratory of Data Analysis and ComputationGuangxi Key Laboratory of Automatic Detecting Technology and InstrumentsGuilin University of Electronic TechnologyCenter for Applied Mathematics of Guangxi(GUET)Guilin 541004China School of Mathematical Sciences South China Normal UniversityGuangzhou 510000China School of Mathematics and Computing Science Guilin University of Electronic TechnologyGuilin 541004China School of Mathematics and Computing Science Guangxi Colleges and Universities Key Laboratory of Data Analysis and ComputationGuilin University of Electronic TechnologyCenter for Applied Mathematics of Guangxi(GUET)Guilin 541004China School of Mathematics and Statistics Yunan UniversityKunming 650000China

The truncated singular value decomposition has been widely used in many areas of science including engineering,and statistics,*** this paper,the original truncated complex singular value decomposition problem is formulated as a Riemannian optimiza-tion problem on a product of two complex Stiefel manifolds,a practical algorithm based on the generic Riemannian trust-region method of Absil et *** presented to solve the underlying problem,which enjoys the global convergence and local superlinear conver-gence *** experiments are provided to illustrate the efficiency of the proposed *** with some classical Riemannian gradient-type methods,the existing Riemannian version of limited-memory BFGS algorithms in the MATLAB toolbox Manopt and the Riemannian manifold optimization library ROPTLIB,and some latest infeasible methods for solving manifold optimization problems,are also provided to show the merits of the proposed approach.

关键词： Truncated singular value decomposition Riemannian optimization Trust-region method

Trimethylamine N-oxide generation process was influenced by the proportion and source of macronutrients in the diet

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Food Science and Human Wellness 2024年第2期13卷 649-658页

作者： Chengcheng Wang xuefeng duan Xiaoyue Li Jinyue Yang Changhu Xue Teruyoshi Yanagita Tiantian Zhang Yuming Wang College of Food Science and Engineering Ocean University of ChinaQingdao 266003China Laboratory for Marine Drugs and Bioproducts Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Laboratory of Nutrition Biochemistry Department of Applied Biochemistry and Food ScienceSaga UniversitySaga 840-8502Japan

Trimethylamine N-oxide(TMAO)is a risk factor of various chronic diseases,which was produced by metabolism from precursors to trimethylamine(TMA)in gut and the oxidation from TMA in *** TMA generation was influenced by diet,mainly due to the rich TMAO precursors in ***,it was still unclear that the effects of different proportion and source of macronutrients in different dietary pattern on the production process of ***,the generation of TMA from precursors and TMAO from TMA was determined after single oral choline chloride and intraperitoneal injection TMA,respectively,in mice fed with carbohydrates,proteins and fats in different proportion and *** results suggested that the generation of TMAO was increased by low non-meat protein and high fat via enhancing the production of TMAO from TMA,and decreased by plant protein and refined sugar via reducing TMA production from precursors in gut and TMAO transformation from TMA in *** high fat and high sugar diets accelerating the development of atherosclerosis did not increase the production of TMAO,the risk factor for atherosclerosis,which indicated that the dietary compositions rather than the elevated TMAO level might be a more key risk factor for atherosclerosis.

关键词： Trimethylamine N-oxide(TMAO) Trimethylamine(TMA) Dietary composition Macronutrients Gut microbiota

Dykstra’s Algorithm for the Optimal Approximate Symmetric Positive Semidefinite Solution of a Class of Matrix Equations

在线全文

学校读者我要写书评

暂无评论

Advances in Linear Algebra & Matrix Theory 2016年第1期6卷 1-10页

作者： Chunmei Li xuefeng duan Zhuling Jiang College of Mathematics and Computational Science Guilin University of Electronic Technology Guilin China

Dykstra’s alternating projection algorithm was proposed to treat the problem of finding the projection of a given point onto the intersection of some closed convex sets. In this paper, we first apply Dykstra’s alternating projection algorithm to compute the optimal approximate symmetric positive semidefinite solution of the matrix equations AXB = E, CXD = F. If we choose the initial iterative matrix X0 = 0, the least Frobenius norm symmetric positive semidefinite solution of these matrix equations is obtained. A numerical example shows that the new algorithm is feasible and effective.

关键词： Matrix Equation Dykstra’s Alternating Projection Algorithm Optimal Approximate Solution Least Norm Solution

Natural killer cells are activated and play a protective role against ZIKA virus infection in mice

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science Bulletin 2017年第14期62卷 982-984页

作者： xuefeng duan Shihua Li Gary Wong Dongfang Wang Haoyu Wang Jiao Lu Yuhai Bi Xuancheng Lu Yi Shi Jinghua Yan Min Fang George Fu Gao CAS Key Laboratory of Pathogenic Microbiology and Immunology Institute of Microbiology Chinese Academy of Sciences University of Chinese Academy of Sciences Institute of Health Sciences Anhui University Laboratory Animal Center Chinese Center for Disease Control and Prevention (China CDC) International College University of Chinese Academy of Sciences National Institute for Viral Disease Control and Prevention Chinese Center for Disease Control and Prevention (China CDC) Savaid Medical School University of Chinese Academy of Sciences Research Network of Immunity and Health (RNIH) Beijing Institutes of Life Science Chinese Academy of Sciences

Zika virus(ZIKV)is a mosquito-borne Flavivirus that was responsible for an epidemic in the Americas during 2015–2016[1].ZIKV infections in adults have been linked to Guillain-Barrésyndrome[2,3],as well as abnormalities such as abortion,stillbirth,and microcephaly in some cases[4].In addition,we have reported that ZIKV infect testicular stem-like peritubular

关键词：病毒感染细胞活性保护作用杀伤自然小鼠对齐

Computing Approximation GCD of Several Polynomials by Structured Total Least Norm

在线全文

学校读者我要写书评

暂无评论

Advances in Linear Algebra & Matrix Theory 2013年第4期3卷 39-46页

作者： xuefeng duan Xinjun Zhang Qingwen Wang College of Mathematics and Computational Science Guilin University of Electronic Technology Guilin China Department of Mathematics Shanghai University Shanghai China

The task of determining the greatest common divisors (GCD) for several polynomials which arises in image compression, computer algebra and speech encoding can be formulated as a low rank approximation problem with Sylvester matrix. This paper demonstrates a method based on structured total least norm (STLN) algorithm for matrices with Sylvester structure. We demonstrate the algorithm to compute an approximate GCD. Both the theoretical analysis and the computational results show that the method is feasible.

关键词： Sylvester Matrix Approximate Greatest Common Divisor Low Rank Approximation Structured Total Least Norm Numerical Method

Performance analysis of the mutual coupling effect on Phased Array Feeds

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Astronomical Techniques and Instruments 2024年第4期1卷 211-217页

作者： Kai Wang Maozheng Chen Jun Ma Hao Yan Liang Cao xuefeng duan Jiahui Li Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Xinjiang Key Laboratory of Microwave Technology Urumqi 830011China

A phased array feed(PAF)is a type of receiving array that places phased array antennas on the focal plane of a radio telescope to expand its field of view and improve observation *** to the mutual coupling effect between elements caused by a tightly arranged feed array,which changes the performance of a PAF,this paper presents a 7×7 rectangular feed array model for a 25 m reflector *** adjusting the element spacings,the performance of a PAF with different spacings is comprehensively analyzed with respect to the mutual coupling effect via performance statistics and *** research aims to provide a reference for the preliminary design of a related PAF.

关键词： Reflector antenna Focal field Phased array Beamforming Mutual coupling

矩阵方程X+A~*X-qA=Q(q≥1)的Hermitian正定解及其扰动分析

在线全文

学校读者我要写书评

暂无评论

高等学校计算数学学报 2008年第3期30卷 280-288页

作者：段雪峰廖安平湖南大学数学与计量经济学院长沙大学数学研究所

The Hermitian positive definite solution of the nonlinear matrix equau- tion X+A*X-qA=Q（q≥1） is *** necessary and sufficient conditions for the existence of a solution are *** iterative method for finding the posit... 详细信息

关键词： nonlinear matrix equation positive definite solution minimal solution iterative method perturbation analysis

基于PIV观测土体动态变形时程的可行性探讨

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

土木工程学报 2022年第S1期55卷 234-240页

作者：段雪锋王永志陈苏袁晓铭中国地震局工程力学研究所地震工程与工程振动重点实验室黑龙江哈尔滨150080 中国地震局工程力学研究所地震灾害防治应急管理部重点实验室黑龙江哈尔滨150080 中国地震局地球物理研究所北京100081

图像变形量测技术在分析土体变形矢量场和等势云图方面已获得广泛应用,但在获取土体动态变形时程方面目前尚未见探讨。为探明图像变形测量在土体动态变形时程观测中的可行性与基本要求,结合土体图像与变形模拟方法,利用PIV量测技术,分... 详细信息

图像变形量测技术在分析土体变形矢量场和等势云图方面已获得广泛应用,但在获取土体动态变形时程方面目前尚未见探讨。为探明图像变形测量在土体动态变形时程观测中的可行性与基本要求,结合土体图像与变形模拟方法,利用PIV量测技术,分别对不同动荷载频率、图像采集帧率、应变计算窗口、应变大小等情况的图像测量结果作出分析,并提出动态窗口应变分析算法计算动态应变。研究表明:在实现位移时程与加速度时程观测时,正弦波的图像采集帧率应≥6倍输入波频率,Northridge波、LomaGilroy波、Tangshan波的图像采集帧率需分别≥20Hz、≥10Hz和≥6Hz;大比例应变计算窗口可有效缩小应变场的离散性,但会导致非均恒分布应变的计算结果偏离真值;提出的动态窗口应变分析算法可兼顾计算结果的平滑度与精准度,更有利于动态应变分析。

关键词：动态变形图像测量位移时程应变分析可行性

同方期刊数据库

在线全文

学校读者我要写书评

暂无评论

低剂量胸部CT扫描诊断肺癌的效果观察

影像研究与医学应用 2020年第5期4卷 39-40页

作者：端雪峰鲁北高新技术开发区人民医院放射科山东滨州251900

目的:分析低剂量胸部CT在扫描诊断肺癌方面的临床效果与临床价值。方法:研究对象选择2017年12月至2018年12月期间在我院进行肺癌筛查的96例患者。将患者随机划分为观察组和对照组,每组48例。对照组进行常规胸部X线检查,观察组则进行低... 详细信息

目的:分析低剂量胸部CT在扫描诊断肺癌方面的临床效果与临床价值。方法:研究对象选择2017年12月至2018年12月期间在我院进行肺癌筛查的96例患者。将患者随机划分为观察组和对照组,每组48例。对照组进行常规胸部X线检查,观察组则进行低剂量胸部CT检查,比较两组患者在结节大小和检出率方面的数据差异,判定诊断方式的有效性。结果:研究结果显示,观察组使用低剂量胸部CT扫描在结节检出率(41.7%)方面要明显优于对照组使用胸部X线检查(10.4%),在5mm以下、5~10mm、10~20mm与20mm以上结节检出数量上差异明显(P<0.05),数据结果具有统计学意义。结论:低剂量胸部CT在结节检出率方面优于传统的胸部X线检查,可以给今后疑似肺癌疾病的诊断、灵敏度和阴性预测等方面提供良好的技术支持。

关键词：低剂量胸部CT 扫描肺癌诊断效果观察